Bug 443529

Summary:	Cannot enter fullscreen on Firefox
Product:	[Plasma] kwin	Reporter:	Jeff <ddg10595>
Component:	general	Assignee:	KWin default assignee <kwin-bugs-null>
Status:	RESOLVED NOT A BUG
Severity:	minor	CC:	kde
Priority:	NOR
Version First Reported In:	5.22.5
Target Milestone:	---
Platform:	Fedora RPMs
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:

Description Jeff 2021-10-09 22:32:46 UTC

SUMMARY
Trying to fullscreen a video in firefox results in a black screen until you are able to exit.

STEPS TO REPRODUCE
1. Open Firefox
2. Play a video on any site (I used YouTube)
3. Attempt to fullscreen the video

OBSERVED RESULT
You're given a black screen that will stay there until you are able to exit fullscreen

EXPECTED RESULT
The video going into fullscreen mode.

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: Fedora 34
KDE Plasma Version: 5.22.5
KDE Frameworks Version: 5.85.0
Qt Version: 5.15.2

ADDITIONAL INFORMATION
This is my first bug report, sorry if I did any of this wrong. This problems doesn't happen in Gnome. 

setting full-screen-api.ignore-widgets to true in about:config somewhat fixes the issue, the top window border is still there though and I don't think its a proper solution. 

This line is also in my journalctl:
Oct 09 15:29:16 fedora kwin_x11[2724]: qt.qpa.xcb: QXcbConnection: XCB error: 3 (BadWindow), sequence: 24833, resource id: 113246216, major code: 18 (ChangeProperty), minor code: 0

I'm 99% sure they are related, as the error happens when I try to fullscreen.
Thanks.

Comment 1 David Edmundson 2021-10-09 23:24:02 UTC

Do other things go full screen ok? If so report to FF first.

Comment 2 Jeff 2021-10-09 23:55:14 UTC

(In reply to David Edmundson from comment #1)
> Do other things go full screen ok? If so report to FF first.

Yeah, other things work fine, This issue doesnt happen with Gnome though, so I figured I would report it here. If not i'll file on with FF.

Comment 3 David Edmundson 2021-10-10 23:04:14 UTC

This is X or wayland?

If wayland, please share output of `WAYLAND_DEBUG=1 firefox`.

We can see what FF asks kwin to do and what we get back.